In non-obstructive azoospermia (NOA), no spermatozoa are present in the ejaculate as a result of compromised or absent spermatogenesis. NOA is distinguished from obstructive azoospermia by patient history, clinical examination and hormone profile. As much as 10% of all male infertility has been attributed to NOA1. In contrast to obstructive azoospermia, men with NOA tend to have elevated FSH levels, and low testosterone levels; testicular volume tends to be significantly reduced and testicular consistency soft.